The invention relates to augmentation mammoplasty and reconstructive breast surgery and to an improved breast prostheses.
Conventional breast prostheses generally are constructed as a single unit containing gelatinous material such as silicone gel surrounded by a single envelope typically made of silicone. These prostheses are placed under the subcutaneous tissue of the breast or under the pectoralis muscle. The effect of the prosthesis is to enlarge the base of the breast. However, in many cases, and in particular after breast resection, enough subcutaneous tissue may not be present to provide adequate projection of the breast. The insertion of a larger prosthesis simply results in a pancaking effect since the prosthesis is soft to provide the normal feel of breast tissue and therefore tends to flatten. Increasing the viscosity of the gel within the breast can result in less flattening of the prothesis. However, this also results in an abnormal sense of firmness of the breast. To compensate, a technique of stacking one prosthesis on top of another during surgical implantation of the breast has been proposed. However, such a technique can result in a flattening of both prostheses and is technically more difficult than the insertion of a single prosthesis.
A second problem relates to the formation of capsular contractures associated with tissue reaction to the implanted prosthesis. This problem is well known in the art and causes an abnormal sense of firmness of the enhanced breasts in a substantial percentage of patients.
In general, the improved breast prosthesis of the present invention is formed as a conical or pyramidal implant having a base which has a larger surface area than the apex which is preferably rounded. In the preferred embodiment the prosthesis includes a plurality of compartments which are surrounded by a single envelope or housing means. The base compartment has a larger surface area to volume ratio and therefore is more easily deformable than the more apical compartments. In other words, the walls of the basilar compartment which are adapted to be positioned relatively proximally are stretched less than the walls of the apical compartment which are adapted to be positioned relatively distally and therefore the internal pressure is less as well.
In the preferred embodiment three compartments are provided, each with a progressively decreasing exterior surface area to volume ratio from the base to the apex. The compartments may be attached one to another as by adhesive and covered by a single envelope or they may be preferably integral, one with another, comprising individual compartments of a single pyramidal structure.
Each compartment is preferably filled with suitable permanently deformable material such as conventional silicone. The surrounding envelope is preferably porous polytetrafluoroethylene, (PTFE) which can be obtained under the trade name GORTEX. The assembled prosthesis, when placed upon it's base, will assume a substantially conical shape having a rounded apex. The apical compartment will have a slighter firmer feel to palpation than the basilar compartment.
In operation the prosthesis is placed under the breast tissue or pectoralis muscle with the apex facing outwardly or distally. The feel of the prosthetically enhanced breast will be substantially natural in that, while the apex of the breast is firmer than the base, pressure upon the apex results in basilar deformation thereby reducing the perception of apical firmness. However, the firmness of the apical portion produces the appearance of projection which is considered more aesthetically appealing to the patient. The porous polytetrafluoroethylene envelope or housing means provides a novel interface between the breast implant and the patient's surrounding tissue. This may potentially reduce capsular contracture and therefore reduce the perception of excessive firmness which may develop with conventional implants.